EP2610499B1 - Pump power unit - Google Patents

Description

The invention relates to a pump unit with the features specified in the preamble of claim 1.

In pump units with a designed as a canned motor electric drive motor, such as circulating pump units for heating systems, a bearing is usually located inside a canned pot, in which an axial end of a motor shaft is mounted in the radial direction. To attach this bearing, it is known to weld to the axial end of the can, a bearing holder in which the bearing is received. This bearing holder then usually has a smaller inner diameter than the adjacent split tube. This construction of the can with the welded bearing holder is relatively expensive.

DE 41 08 257 A1 shows a magnetic coupling pump with a magnetic coupling in which an outer magnet rotor is separated from an inner magnet rotor by a split pot. The inner magnet rotor is fixed in its interior to a shaft which is mounted in a bearing which is mounted in a concentric with the shaft extending projection, wherein the projection extends from the open end of the can into this. So the storage is located inside the inner magnet rotor.

DE 10 2006 053 479 A1 discloses a motor centrifugal pump with an electric drive motor designed as a canned motor. In this case, the split tube is designed so that it faces away from the impeller Axial end is closed by a sheet-metal molded body, which forms an axial extension of the split tube with a smaller diameter, in which a bearing for the rotor shaft is arranged. That is, here a separate component for closing the gap tube is provided at the axial end.

US 4,944,611 discloses a sealed ball bearing in which an outer bearing ring is disposed in a die-cast housing, wherein the outer bearing ring is surrounded at the axial ends of a metal jacket, which keeps excessive temperature influences from the bearing when pouring into the housing. This jacket can be formed wavy.

Another ball bearing assembly is off US 3,960,418 known. Another sliding bearing assembly is made DE 78 36 469 U1 known.

It is an object of the invention to improve a pump unit with a canned motor to the effect that a bearing can be arranged in a simpler manner on a canned pot, at the same time a simplified construction of the can is possible.

This object is achieved by a pump unit having the features specified in claim 1. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

The pump unit according to the invention has an electric drive motor, which is designed in a known manner as a canned motor and forms a structural unit with the actual pump. The Canned pipe is designed as a canned pot, that is, an axial end of the can, namely the impeller of the pump remote from the axial end of the can is closed. Such a canned pot can be made in a known manner, for example, metal, in particular stainless steel. In this case, the canned pot can be made in particular as a deep-drawn part. Inside the canned pot, a bearing for supporting a motor shaft is arranged. The bearing is arranged near the closed end of the canned pot. The bearing has an outer diameter which is smaller than the inner diameter of the canned pot. That is, the canned pot is preferably not tapered in the region in which the bearing is arranged.

To the bearing, which has a smaller outer diameter than the inner diameter of the canned pot, still fix and store in the canned pot, a bearing holder is provided which fills the space between the outer diameter of the bearing and inner diameter of the canned pot and centered the bearing centered in the canned pot. For this purpose, the bearing holder has a plurality of webs extending transversely to the inner circumference of the can. That is, the storekeeper is not designed as a solid material. The webs are preferably spaced apart in the circumferential direction and distributed over the circumference. Particularly preferably, the webs are distributed uniformly over the circumference in order to transmit radial forces in all directions evenly from the camp to the canned pot. The bearing holder is preferably made as a separate component, which is used after the production of the canned pot in this. The bearing can be placed in the cradle before inserting the bearing holder in the canned pot, or even after inserting the bearing holder in the canned pot. The bearing is further preferred on its inner circumference after insertion into the canned pot ground to ensure centering of the bearing surfaces with respect to the inner diameter of the canned pot.

The webs extend transversely to the inner circumference of the can, that is preferably substantially radially to the longitudinal axis of the canned pot, that is to the axis of rotation of the motor shaft. The webs and preferably the entire bearing holder may be formed for example of plastic or metal.

Particularly preferably, the webs are formed from a flat material, in particular a sheet, which has a wall thickness which is less than the radial distance between the outer circumference of the bearing and the inner circumference of the can. That is, this flat material extends with its surfaces transversely, in particular radially to the inner circumference of the canned pot or to the longitudinal axis of the canned pot.

Preferably, a plurality of webs may be integrally formed by a circumferentially wavy and / or zigzag running shaped flat material. That is, this flat material always changes its direction of extension so that webs are formed, which extend transversely or in particular substantially radially to the inner circumference of the canned pot. In this case, the webs which are formed in sections can also extend at an angle, in particular at an acute angle to the radius. The wave-shaped or zigzag-shaped form can in particular be produced by forming the flat material or sheet metal. The zigzag or wavy profile in cross-section preferably extends over the entire outer circumference of the bearing support and fills the free space between the inner circumference of the canned pot and the outer circumference of the bearing. In this case, the vertices or apex areas of the wave-shaped or zigzag-shaped flat material come on the inner circumference of the Spaltohrtopfes and on the outer circumference of the bearing to the plant and thus ensure the radial fixation of the bearing inside the canned pot and for the transmission of power from the bearing on the canned pot in the radial direction.

Preferably, the flat material extends over the entire circumference, in particular as a closed ring. In this way, the bearing over the entire circumference is radially fixed or stored in the interior of the canned pot.

The bearing holder is preferably dimensioned relative to the bearing so that the bearing is fixed non-positively in the interior of the bearing. That is, the bearing holder has an inner diameter, which is preferably slightly smaller than the outer diameter of the bearing, so that it comes at the onset of the bearing to a deformation of the bearing holder, which leads due to elastic restoring forces to a frictional bearing of the bearing holder on the outer circumference of the bearing.

Further, the bearing holder is preferably dimensioned relative to the inner circumference of the canned pot so that the bearing holder is fixed non-positively in the interior of the canned pot. For this purpose, the bearing holder, if it is not inserted into the canned pot, preferably an outer diameter which is slightly larger than the inner diameter of the canned pot, so that the bearing holder is elastically deformed when inserted into the canned pot and is fixed so non-positively on the inner wall of the canned pot , The elastic deformability of the bearing holder for the non-positive fixing of the bearing and / or the non-positive fixing of the bearing holder in the interior of the canned pot can be done by a deformation of the individual, extending transversely to the inner circumference of the split tube webs or by deformation of the webs to each other.

The storekeeper is particularly preferably formed from sheet metal. The shaping can be done in particular by deep drawing. For example, the bearing holder can be made from a round sheet metal by first forming a cup-shaped shape by deep-drawing. Subsequently, a wave-shaped structure can be formed in the peripheral wall and, if appropriate, the end face of this cup-shaped form by the circumferential wall being pressed inward in the radial direction at several points inwardly and / or outwardly. Finally, in the last step, the bottom or a central region of the bottom can be punched out of this cup-shaped structure with recesses or corrugations. In this way, such a bearing holder made of sheet metal can be completely finished by forming and stamping, without a machining or thermal processing is required. Furthermore, the bearing holder can be formed in one piece. Thus, a closed ring structure without welding or joining operations can be generated.

Particularly preferably, the bearing holder has at least one radially inwardly directed axial stop on which the bearing comes to rest with an axial end. This stop is preferably formed on the bottom of the canned pot facing side of the bearing holder and in turn is preferably at the bottom of the canned pot on. This stop fixes the bearing in the axial direction and prevents the bearing from slipping out of the bearing holder in the axial direction or being pushed too far into the bearing holder in the axial direction.

The radially inwardly directed stop is more preferably formed by a radially inwardly extending circumferential collar. Such a collar can easily be formed by deep drawing in the manufacturing method described above, by not completely removing the bottom of the cup-shaped structure, but only a central area is removed, so that on the inner circumference of the bearing holder an annular portion of the bottom is maintained as a circumferential collar.

According to a particularly preferred embodiment, the bearing holder has at least one channel extending completely through the bearing holder in the axial direction. This channel allows fluid to be delivered, for example, water to flow through the bearing holder and thus reach the rear of the bearing so that the bearing is completely lapped. This is advantageous since the lubrication of the bearing is usually carried out by the liquid to be conveyed. Such a channel or several channels can be formed by spaced webs of the bearing holder. The free spaces between the webs form such channels. The free spaces extend from one axial end to the opposite axial end of the bearing holder. In the case of a shaft-shaped or zigzag-shaped structure of the bearing holder, the channels are formed by the indentations formed in the radial direction, that is to say the free cross-sectional areas formed by the undulating or zigzag-shaped structure.

More preferably, in the stop at least one radially extending channel is formed, which is preferably connected at its radially outer end with a extending in the axial direction through the bearing holder channel. This channel allows liquid passing through the bearing retainer or circumferentially past the bearing retainer to flow radially inward toward the bearing or bearing surfaces of the bearing at the rear of the bearing retainer to provide adequate lubrication there. The channel at the stop or the channels in the stop are preferably located on the side facing the bearing, but may additionally or alternatively also located on the side facing the bottom of the canned pot be. Preferably, the radially extending channels extend as extensions of the axially extending channels. When forming an initially cup-shaped deep-drawn sheet such channels can be created by indentations or bulges of the sheet, which are distributed over the circumference, preferably distributed uniformly over the circumference in the sheet, are created. In this case, the bottom plate of the cup-shaped structure is provided in accordance with indentations or bulges. Then, when the central area of the floor panel is punched out, a wavy or jagged structure remains in the circumferential collar, defining on the surfaces the radially extending channels.

The bearing holder is suitably designed and arranged in the canned pot so that the bearing is positioned axially spaced from a bottom of the canned pot. In this case, preferably, the bearing holder with its axial end face, preferably with the outside of its radially inwardly extending stop or collar at the bottom of the canned pot. Thus, the bearing holder holds the bearing at a defined distance from the bottom of the canned pot. If the radially inwardly directed collar or stop of the bearing holder is formed in the manner described above with radially inwardly extending channels, for example by a wave-shaped structure of the collar, it is ensured that liquid flow between the bearing and the bottom of the can and so the bearing can flow around the back to provide adequate lubrication on the bearing surfaces.

The canned pot can have a reduced wall thickness in an axial region in which a rotor is arranged, that is to say in the axial region in which the magnetically active components of the rotor are arranged. As a result, the magnetic efficiency between stator and rotor can be improved. The storekeeper, however, is preferably arranged in an axial region with not reduced wall thickness. Thus, sufficient stability of the canned pot for receiving the forces transmitted from the bearing is created in the region of the bearing. A thinning of the wall canned pot can be done for example by pressing or rolling. In this case, the bottom of the canned pot facing axial end of the canned pot is not processed, so that this area, in which then the bearing holder is arranged with the camp, is not thinned. Except for such a reduced wall thickness by thinning the wall thickness, however, the canned pot preferably has substantially the same diameter over its entire axial length.

The pump unit according to the invention is particularly preferably designed as a circulating pump unit, in particular as a heating circulation pump unit.

Fig. 1

eine teilweise geschnittene perspektivische Gesamtansicht eines erfindungsgemäßen Pumpenaggregats,

Fig. 2

eine teilweise geschnittene perspektivische Ansicht des Spaltrohrtopfes des Pumpenaggregats gemäß Fig. 1 von der dem Laufrad zugewandten Seite,

Fig. 3

eine perspektivische teilweise geschnittene Ansicht des Spaltrohrtopfes gemäß Fig. 2 von der Rückseite her gesehen,

Fig. 4

eine perspektivische Ansicht des Lagerhalters von der Rückseite her gesehen, und

Fig. 5

eine perspektivische Gesamtansicht des Lagerhalters gemäß Fig. 4 von seiner Vorderseite gesehen.

The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

Fig. 1

a partially sectioned overall perspective view of a pump unit according to the invention,

Fig. 2

a partially cutaway perspective view of the canned pot of the pump unit according to Fig. 1 from the side facing the impeller,

Fig. 3

a perspective partially sectioned view of the canned pot according to Fig. 2 seen from the back,

Fig. 4

a perspective view of the bearing holder seen from the back, and

Fig. 5

an overall perspective view of the bearing holder according to Fig. 4 seen from its front.

The pump set according to Fig. 1 is a Heizungsumwälzpumpenaggregat, which has a pump housing 2 with a suction nozzle 4 and a discharge nozzle 6 in a known manner. In the pump housing 2, an impeller 8 is arranged. Attached to the pump housing 2 is a stator housing 10 with a stator 12 of an electric drive motor arranged therein. The electric drive motor is designed as a canned motor. That is, inside the stator 12, there is arranged a canned pot 14 which, via a collar 16 protruding radially outwards, locates the region of the stator housing 10 in which the stator 12 is located, to the interior of the pump housing 2 in which the fluid to be delivered is located , seals. Inside the canned pot 14, a rotor 18 is arranged, which rotatably drives the impeller 8 via the motor shaft 20. The motor shaft 20 is mounted at its axial end facing away from the impeller 8 in a radial bearing 22. The radial bearing 20 is in turn fixed in a bearing holder 24 in the interior of the canned pot 14.

The design and function of the bearing holder 24 will be described in more detail with reference to the Fig. 2 to 5 described. The canned pot 14 has at its open end the radially outwardly directed collar 16. At its opposite axial end of the canned pot 14 is closed by a bottom 26.

In the adjoining the collar 16 axial portion 28 of the canned pot 14 whose wall is thinned or formed with reduced thickness in order to improve the magnetic flux between the stator 12 and rotor 18 in this area. In the adjacent to the bottom 26 axial region 30 of the canned pot 14 whose wall thickness is not reduced. In this area, the bearing holder 24 is arranged with the radial bearing 22 arranged therein. The radial bearing 22 is preferably designed as a sliding bearing, for example made of ceramic.

The bearing holder 24 is formed as a deep-drawn part made of sheet metal. The bearing holder 24 has a pot-shaped basic shape, wherein the central region 32 of the bottom of this pot-shaped structure is preferably removed by punching, so that an open central region 32 is formed. The peripheral wall 34 has a wave-shaped structure, wherein the radially outer apex regions 36 on the inner circumference of the canned pot 14 frictionally come to rest, while the radially inner apex portions 38 of the undulating structure of the peripheral wall 34 come frictionally on the outer circumference of the radial bearing 22 to the plant. Thus, the wave-shaped circumferential wall 34 fills the clearance between the radial bearing 22 and the inner circumference of the canned pot 14 and fixes and centers the radial bearing 22 inside the canned pot 14. For centering the inner peripheral surface of the radial bearing 22, which forms the bearing surface, with respect to the longitudinal or rotation axis X, the radial bearing 22 is preferably ground after insertion into the canned pot 14.

The wave-shaped structure of the circumferential wall 34 is achieved in that the radially outer apex regions 36 and the radially inner vertex regions 38 alternate regularly distributed over the circumference. Such a structure can be achieved for example by forming a previously cylindrical pot. By this wave-shaped structure are transverse to the inner circumference of the canned pot, that is substantially radially to the axis of rotation X directed webs 40 created, which connect the apex portions 36 and 38 together. The webs 40 serve to center the bearing 22 in the canned pot 14 and to transfer the radial forces from the radial bearing 22 on the peripheral wall of the canned pot 14th

The wave-shaped structure 40 free spaces 42 are formed on the inner circumference of the peripheral wall 34 of the bearing holder 24 between the webs. These free spaces 42 thus lie radially within the apex regions 36. Accordingly, intermediate free spaces are formed radially outside the inner apex regions 38 on the outer side of the peripheral wall 34. These free spaces 42 and the free spaces 44 on the outer circumference form axially extending over the entire length of the bearing holder 24 channels through which liquid in the interior of the canned pot 14 can flow from the pump housing 2 side facing through the bearing holder 24 to the back of the radial bearing 22 ,

Starting from the peripheral wall 34, the bearing holder 24 also has a radially inwardly directed collar 46 at an axial end. This radially inwardly directed collar 46 is formed as an annular collar. The annular collar 46 represents the outer region of the bottom of the cup-shaped structure of the bearing holder 24, which remains after punching out of the central region 32. The collar 46 serves as an axial stop for the radial bearing 22 when it is inserted or pressed into the bearing holder 24 from the open, that is the collar 46 facing away from the axial side. In addition, the collar 46 can come to rest with its outside in the interior of the canned pot 14 at the bottom 26. Thus, the collar 46 then holds the radial bearing 22 at a distance from the bottom 46. The free-spaces 42 acting as channels on the inner circumference of the peripheral wall 34 of the bearing holder 24 open on the inside of the collar 46 in radially inwardly extending channels 48. In this way, liquid , which flows through the free spaces 42 in the axial direction, directed radially inwardly via the channels 48 on the collar 46, so that the radial bearing 22 flows around the back.

Overall, it can be seen that a very simple fixation of the radial bearing 22 in the interior of the canned pot 14 is possible and at the same time the flow around the radial bearing 22 is ensured with liquid by the formed as a deep-drawn part of sheet metal bearing holder 24. The bearing holder 24 is dimensioned so that its outer diameter in the region of the outer apex regions 36 is slightly larger than the inner diameter of the canned pot 14. Thus, the bearing holder 24 can be pressed into the interior of the canned pot 14 and held frictionally in the axial region 30. At the same time, the inner diameter in the region of the inner apex regions 38 of the bearing holder 24 is preferably slightly smaller than the outer diameter of the radial bearing 22, so that the radial bearing 22 can be pressed into the interior of the bearing holder 24 and fixed there in a non-positive manner.

LIST OF REFERENCE NUMBERS

2

- Pump housing

4

- Suction nozzle

6

- discharge nozzle

8th

- Wheel

10

- stator housing

12

- stator

14

- Canned pot

16

- collar

18

- Rotor

20

- Motor shaft

22

- Radial bearings

24

- storekeeper

26

- Ground

28

- axial area

30

- axial area

32

- Central area

34

- peripheral wall

36, 38

- vertex areas

40

- Footbridges

42, 44

- Freiräume

46

- collar

48

- Channels

X

- longitudinal or rotary axis

Claims (17)

1. A pump assembly with an electric drive motor which is designed as a canned motor and which in the inside of a can pot (14) comprises a bearing (22), in which a motor shaft (20) is mounted, characterised in that
   the bearing (22) has an outer diameter which is smaller than the inner diameter of the can pot (14), and the bearing (22) is mounted in the inside of the can pot (14) in a bearing holder (24) which comprises several webs (40) extending transversely to the inner periphery of the can pot (14), fills the free space between the outer diameter of the bearing (22) and the inner diameter of the can pot (14) and fixes the bearing (22) in the can pot (14) in a centred manner.
2. A pump assembly according to claim 1, characterised in that the can pot (14) is designed of metal, in particular of a rust-free steel.
3. A pump assembly according to claim 1 or 2, characterised in that the webs (14) are formed from a flat material, in particular of a sheet metal, which has a wall thickness which is smaller than the radial distance between the outer periphery of the bearing (22) and the inner periphery of the can pot (14).
4. A pump assembly according to one of the preceding claims, characterised in that several webs (40) are formed as one piece from a flat material which in the peripheral direction is shaped running in a wave-like and/or zigzag manner.
5. A pump assembly according to claim 4, characterised in that the flat material extends over the whole periphery, preferably as a closed ring.
6. A pump assembly according to one of the preceding claims, characterised in that the bearing holder (24) is dimensioned relative to the bearing (22) such that the bearing (22) is fixed with a non-positive fit in the inside of the bearing holder (24).
7. A pump assembly according to one of the preceding claims, characterised in that the bearing holder (24) is dimensioned relative to the inner diameter of the can pot (14) such that the bearing holder (24) is non-positively fixed in the inside of the can pot (14).
8. A pump assembly according to one of the preceding claims, characterised in that the bearing holder (24) is formed from sheet metal, in particular by way of deep drawing.
9. A pump assembly according to one of the preceding claims, characterised in that the bearing holder (24) comprises at least one radially inwardly directed axial abutment (46), on which the bearing (22) comes into contact with an axial side.
10. A pump assembly according to claim 9, characterised in that the at least one abutment is formed by a radially inwardly extending, peripheral collar (46).
11. A pump assembly according to one of the preceding claims, characterised in that the bearing holder (24) comprises at least one channel (42) extending in the axial direction (X) completely through the bearing holder (24).
12. A pump assembly according to claim 11, characterised in that several channels extending in the axial direction (X) through the bearing holder (24) are formed by free spaces (42) between the webs (40) of the bearing holder (24).
13. A pump assembly according to claim 9 or 10, characterised in that at least one radially extending channel (48) is formed in the abutment (46), said at least one channel at its radially outer end being connected preferably to a channel (42) extending in the axial direction (X) through the bearing holder (24).
14. A pump assembly according to one of the preceding claims, characterised in that the bearing holder (24) is designed and arranged in the can pot (14), in a manner such that the bearing (22) is positioned axially distanced to a base (26) of the can pot (14).
15. A pump assembly according to one of the preceding claims, characterised in that the can pot (14) has an essentially constant diameter over its whole length.
16. A pump assembly according to one of the preceding claims, characterised in that the can pot (14) in an axial region (28), in which a rotor (18) is arranged, has a reduced wall thickness and the bearing holder (14) is arranged in an axial region (30) with a wall thickness which is not reduced.
17. A pump assembly according to one of the preceding claims, characterised in that it is designed as a circulation pump assembly, in particular a heating circulation pump assembly.

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